Work holder

ABSTRACT

A work holder or positioner for forms is provided which retains forms for continuous grinding of round or square end forms without the use of cams or templates, the forms being held in a turntable which indexes and also travels horizontally for engagement by a grinding wheel with the form to be ground.

United States Patent Patch WORK HOLDER [72] Inventor: Richard D. Patch, Drexel Hill, Pa.

[73] Assignee: Castle Tool Specialty Co. Inc., Lansdowne,

[22] Filed: Oct.5, 1970 [21] Appl.No.: 78,060

[52] U.S.Cl. ..51/216 R,51/97 NC,5l/232 [51] Int. Cl .324!) 41/06 [58] Field of Search ..5 l/2l6, 232,105, 97 NC, DIG. 14

[56] References Cited UNITED STATES PATENTS 276,084 4/1883 Schwarz ..51/97 NC 2,421,548 6/1947 Davies ..5 l/DlG. 14

[451 Mar. 28, 1972 Primary ExaminerHarold D. Whitehead Attorney-Zachary T. Wobensmith, 2nd

[5 7] ABSTRACT A work holder or positioner for forms is provided which retains forms for continuous grinding of round or square end forms without the use of cams or templates, the forms being held in a turntable which indexes and also travels horizontally for engagement by a grinding wheel with the form to be ground. 7

9 Claims, 10 Drawing Figures Patented March 28, 1972 3,651,603

4 Sheets-Sheet F5 INVENTOR RICHARD D. PATCH ATTORNEY Patented March 28, 1972 4 Sheets-Shoot 4.

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ATTORNEY WORK HOLDER BACKGROUND OF THE INVENTION 1. Field of the Invention A work holder or positioner for forms is provided of the type in which an indexing and horizontally travelling turntable carries a form to be ground.

2. Description of the Prior Art Round and square end forms are used extensively in tool and die shapes as well as in punch press operations. These forms are usually fabricated by use of a cam guided grinding wheel orwheels travelling over a fixed form which requires a considerable number of cam profiles to produce the sizes and shapes of forms required. In addition difficulties are often encountered in blending the end radius of the round end form with its flat sides resulting in an inaccurately shaped form. The apparatus of the invention provides for accurate radius blending, requires no cams, and is easily set up and operated.

SUMMARY OF THE INVENTION A work holder or positioner is provided which holds forms while round and flat end surfaces are ground on them which holder has an indexing and horizontally travelling turntable for holding the forms for engagement by a grinding wheel.

The principal object of the invention is to provide a work holder for grinding round or flat end forms without the use of pattern cams.

A further object of the invention is to provide a work holder for use while grinding round or flat end forms which produces a very accurately finished form.

A further object of the invention is to provide a work holder for use while grinding round or flat end forms which is simple and inexpensive to construct, has a relatively wide range of adjustment, is easy to use and has a long operating life.

Other objects and advantageous features of the invention will be apparent from the description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawings forming part thereof, in which:

FIG. 1 is a front perspective view illustrating the apparatus of the invention;

FIG. 2 is a horizontal sectional view, enlarged, taken approximately on the line 2-2 of FIG. 1;

FIG. 3 is a vertical sectional view taken approximately on the line 3-3 ofFlG. 2;

FIG. 4 is a vertical sectional view taken approximately on the line 4-4 ofFIG. 2;

FIG. 5 is a vertical sectional view taken approximately on the line 5-5 ofFIG. 2;

FIG. 6 is a fragmentary horizontal sectional view taken approximately on the line 6-6 of FIG. 5;

FIG. 7 is a fragmentary view in elevation illustrating the operation of the apparatus of the invention while grinding one side of a round end form;

FIG. 8 is a view similar to FIG. 7, illustrating the operation of the apparatus while the end of a round end form is being ground;

FIG. 9 is a view similar to FIG. 7 but showing the apparatus in another operating position; and

FIG. 10 is a schematic view illustrating the control circuit of the apparatus.

It should, of course, be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, a grinding wheel G, is shown such as that of a standard surface grinder (not illustrated) for use with the work holder of the present invention and which may be raised or lowered as desired. The work holder includes an outer housing 10, of rectangular configuration having a horizontal base 11, vertical front and rear walls 12 and 14, a removable horizontal top wall 15, and vertical side walls 16 and 17.

A variable speed motor 20 of conventional type is provided mounted on side wall 17 as seen in FIGS. 2 and 3, and having an output shaft 21 with a drive sprocket 22 secured thereon.

The drive sprocket 22 has a chain 23 on it engaged with a drive gear 24, which is mounted on shaft 25 joumaled in drive support members 26 which are also connected to and engaged with output shaft 21.

The shaft 25 has a gear 28 connected thereto which is engaged with a driven gear 30 of considerably larger diameter. The gear 30 is carried on a shaft 31, and has a torque limiter or slip clutch 36 between the gear 30 and the shaft 31 to provide for slippage when needed. The shaft 31 has a mounting arm 35 carried on shaft 25. A bearing ring 37 is secured to shaft 31 and is engaged by a supporting face 380 of follower arm 38 of balance assembly 39 which arm 38 is pivotally secured to a block 40 fastened to right side wall 16. A piston rod 41 from balance cylinder 42 is pivotally secured by a pivot pin 43 to arm 38, the cylinder 42 being pivotally secured by a pivot pin 44 to a block 45 on side wall 17. The balance assembly resiliently urges shaft 31 upwardly and thus restrains it from any downward movement.

An indexing and workholding turntable assembly 50 is provided which includes a rotatable turntable plate 53 with an elongated slot 52 therein through which the shaft 31 extends into threaded engagement with a slide plate 51. The end of the shaft 31 has a lock nut 46 thereon. The shaft 31 is slidable in the slot 52 as hereinafter explained. The shaft 31 has a shoulder 47 engaging a slide thrust plate 48 slidable along the plate 53, the slide tension being adjustable by the threaded engagement of the shaft 31 in the slide plate 51.

The plate 53 is carried in wall 12 in a bearing ring 54 and provided with detents 55 (four being illustrated) secured thereto around its outer periphery. The detents 55 may be respectively engaged by a detent strike arm 56 which is pivotally mounted by pivot pin 57 to block 58 on wall 12.

The strike arm 56 has a piston rod 59 from an actuating cylinder 60 mounted thereon, the rod 59 and strike arm 56 being pivotally connected by pin 61 and to slide plate 62 which has the adjustable stop 65 mounted on wall 12. The cylinder 60 is carried on a pivot pin 63 secured to the wall 12.

Two earns are provided behind the detents 55 on plate 53 and extending partially peripherally. A micro-switch 71 is fastened to front wall 12 and has a roller 72, and arm 73, extending therefrom engageable by the earns 70 when the plate 53 rotates.

The slide plate 51 of the turntable assembly in front of wall 12 has face portions 66 of conventional type to which a form F to be ground is secured in any desired manner, such as by magnetic gripping.

The slide plate 51 has ends 67 which carry exteriorly accessible adjustable stop screws 68 and 69 on each side thereof which extend inwardly for engagement with the turntable plate 53 and by their setting determine the length of the form F.

The actuating switch as seen partially at the left in FIG. 7 is contacted by slide plate 51 at its leftmost positions and through circuitry as shown in FIG. 10 and explained below releases the strike arm 56 from detent engagement so that rotary movement of turntable plate 53 and turntable slide plate 51 can occur.

Referring now to FIG. 10, the fluid control circuit for the apparatus is shown diagrammatically and includes a fluid supply line 100, which is connected to a source of fluid under pressure (not shown). The supply line 100 is connected to a cylinder 42 to cause its piston rod 41, through arm 38 and face 38a to exert a constant upward force upon ring 37 to hold shaft 31 from downward movement but permit horizontal sliding movement of shaft 31 along the face 38a of follower arm 38.

The fluid supply line 100 is also connected to a solenoid valve 75A which is controlled by switch 75 and to a solenoid valve 71A, which is controlled by switch 71 to apply fluid pressure through valve 71A to retract detent strike plate 56 in timed relation as determined by the positioning of the cam plate 70.

The piston rod 59 in cylinder 60 is spring extended and is retracted by fluid pressure controlled by solenoid valve 71A. A manually operable switch controlling a solenoid valve 101 permits separate control for indexing the turntable 50 for forming square end forms.

The mode of operation will now be pointed out.

Assume first that round end forms F are to be ground.

The work positioner of the present invention is preferably located on the table of a standard surface grinder aligned with the center line of the grinding wheel.

The screws 68 and 69 are adjusted in accordance with the length of the form F to be ground, and the micro-switch 75 positioned to be engaged by the slide plate 51 at the ends of its path, thus to conform to the adjusted length. It will be noted that a wide range of adjustment of length is available.

The width of the form F is controlled by the height of the grinding wheel G.

The grinding wheel G is rotated.

The motor 20 is activated and motor shaft 21 drives sprocket 22 which through chain 23 and gear 24 drives gear 28 which is engaged with gear 30. Rotation of gear 30 acts through torque limiter or slip clutch 36 to drive shaft 31.

Rotation of turntable plate 53 is arrested by engagement of detent arm 56 with a detent 55 and since the plate 53 cannot turn slippage will occur at the torque limiter 36 and the force is applied to cause the slide 48 to move in the slot 52, for horizontal grinding until movement of the slide plate 51 is arrested by the stop screw 69 at the end of the horizontal stroke. The micro-switch 75 is effective by actuation of valve 75A to deliver fluid to cylinder 60 to retract detent arm 56, permitting rotary movement of the plate 53 and slide 51 for end grinding.

The plate 53 and slide plate 51 continue to rotate as cam 70 engages switch 71 and continues the application of pressure in cylinder 60 with arm 56 retracted until the plate 53 has rotated through 90 and cam 70 releases switch 71. Pressure is then released from cylinder 60 so that piston rod 59 moves outwardly to move arm 56 to engage a detent 55 which again arrests turning movement and horizontal movement along the slot 52 is again effected until the screw 68 is engaged and micro-switch 75 again engaged for retraction of detent arm 56 and effecting rotation of plate 53 and slide 51 for grinding the other round end of the form F.

The operation will continue until the size is reached, with lowering of the grinding wheel G and final stopping of the machine by the operator.

It may be noted that when the detent arm 56 is retracted and rotary motion commences the action of the balance arm 38 and its face 38a, applies a varying upward force on the slide shaft 31 to prevent the weight of the sliding parts causing overrun of the drive train.

If it is desired to grind forms F with square rather than round ends this can be effected with the positioner.

The slide stop screws 68 and 69 are adjusted for the length desired.

The switch 101 is employed to lock out the cam microswitch 71, and when the slide 51 turns through an angle of the grinding wheel G is caused to traverse the end. The switch 75A is set by the operator to be engaged by the wheel guard (not shown) of the wheel G far enough down the table to allow a time interval for indexing between successive gnnding operations.

The first side is ground, the micro-switch 75A activated by the wheel guard, the slide plate 51 indexes 90 and then the end is ground flat, the micro-switch 75A is again activated and indexes the slide plate 51 through 90. The grinding wheel G passes over the second side either during or after a traverse to stop screw 68. The micro-switch 75 again causes indexing through 90 for grinding the third side. The operation continues repetitively.

I claim:

1. A work positioner for grinding forms having flat and round boundary faces which comprises a housing,

a motor in said housing,

a turntable rotatably mounted in said housing and having a diametrically disposed slot therein,

releasable means holding said turntable against rotation,

a work carrying slide plate having a shaft carried in said slot,

driving means connecting said motor and said shaft including a slip member for effecting sliding movement of said shaft in said slot when said turntable is held against rotation.

2. A work positioner as defined in claim 1 in which said releasable means includes detents carried on said turntable and a detent arm engageable with said detents.

3. A work positioner as defined in claim 1 in which control members are provided for said releasable means,

said control members including a cam movable with said turntable and members actuated by said cam.

4. A work positioner as defined in claim 1 in which said driving means includes a driving gear connected to said slip member, and

a gear engaged with said driving gear and having a pivotal support.

5. A work positioner as defined in claim 4 in which said driving gear is pivotally mounted with respect to said gear engaged therewith.

6. A work positioner as defined in claim 5 in which a resilient supporting member is provided for said driving gear.

7. A work positioner as defined in claim 1 in which a resilient support is provided for said shaft.

8. A work positioner as defined in claim 7 in which said resilient support includes an arm having a surface on which said shaft is movable, and

fluid pressure means is provided connected to said arm.

9. A work positioner as defined in claim 1 in which said releasable means is fluid pressure controlled. 

1. A work positioner for grinding forms having flat and round boundary faces which comprises a housing, a motor in said housing, a turntable rotatably mounted in said housing and having a diametrically disposed slot therein, releasable means holding said turntable against rotation, a work carrying slide plate having a shaft carried in said slot, driving means connecting said motor and said shaft including a slip member for effecting sliding movement of said shaft in said slot when said turntable is held against rotation.
 2. A work positioner as defined in claim 1 in which said releasable means includes detents carried on said turntable and a detent arm engageable with said detents.
 3. A work positioner as defined in claim 1 in which control members are provided for said releasable means, said control members including a cam movable with said turntable and members actuated by said cam.
 4. A work positioner as defined in claim 1 in which said driving means includes a driving gear connected to said slip member, and a gear engaged with said driving gear and having a pivotal support.
 5. A work positioner as defined in claim 4 in which said driving gear is pivotally mounted with respect to said gear engaged therewith.
 6. A work positioner as defined in claim 5 in which a resilient supporting member is provided for said driving gear.
 7. A work positioner as defined in claim 1 in which a resilient support is provided for said shaft.
 8. A work positioner as defined in claim 7 in which said resilient support includes an arm having a surface on which said shaft is movable, and fluid pressure means is provided connected to said arm.
 9. A work positioner as defined in claim 1 in which said releasable means is fluid pressure controlled. 